Tags: baby

Rating:

For a better view check our [githubpage](https://bsempir0x65.github.io/CTF_Writeups/AngstromCTF_2022/#baby3) or [github](https://github.com/bsempir0x65/CTF_Writeups/tree/main/AngstromCTF_2022#baby3) out

So we were given a file that according to the creators does nothing. Instead of real reverse engineering we just started with the strings command to see if the flag is in plain text already present.
console
└─$strings chall /lib64/ld-linux-x86-64.so.2 ?;W( __cxa_finalize __libc_start_main __stack_chk_fail libc.so.6 GLIBC_2.2.5 GLIBC_2.4 GLIBC_2.34 _ITM_deregisterTMCloneTable __gmon_start__ _ITM_registerTMCloneTable PTE1 u3UH actf{emhH <-- whats this hmmm paidmezeH rodollarH stomaketH hischallH enge_amoH gus} ;*3$"
GCC: (GNU) 11.2.0
abi-note.c
__abi_tag
init.c
crtstuff.c
deregister_tm_clones
__do_global_dtors_aux
completed.0
__do_global_dtors_aux_fini_array_entry
frame_dummy
__frame_dummy_init_array_entry
chall.c
__FRAME_END__
_DYNAMIC
__GNU_EH_FRAME_HDR
_GLOBAL_OFFSET_TABLE_
[email protected]_2.34
_ITM_deregisterTMCloneTable
_edata
_fini
[email protected]_2.4
__data_start
__gmon_start__
__dso_handle
_IO_stdin_used
_end
__bss_start
main
__TMC_END__
_ITM_registerTMCloneTable
[email protected]_2.2.5
_init
.symtab
.strtab
.shstrtab
.interp
.note.gnu.property
.note.gnu.build-id
.note.ABI-tag
.gnu.hash
.dynsym
.dynstr
.gnu.version
.gnu.version_r
.rela.dyn
.rela.plt
.init
.text
.fini
.rodata
.eh_frame_hdr
.eh_frame
.init_array
.fini_array
.dynamic
.got
.got.plt
.data
.bss
.comment

As you can see we were already lucky. We just needed to put these together and voila we had the flag actf{emhpaidmezerodollarstomakethischallenge_amogus}.
So this way was a bit to easy so we wanted to understand what happens and actually nothing happens. The program just loads the flag into the memory and then exits. As you can see here:

Original writeup (https://bsempir0x65.github.io/CTF_Writeups/AngstromCTF_2022/#baby3).